Backfilling Sources

Backfill a source's changelog history without the remote extraction inference bill (the update workflow's server-side Haiku / tool-loop passes), using the backfill-source dynamic Workflow (and backfill-sweep for several at once). The Workflow wraps the local-ingest primitives — preflight, fetch + extract, /batch upsert, parity rules — in a deterministic harness that owns the window cap, the budget gate, the dedup, and the safety gate, so the disciplines that are fragile when left to prose are enforced in code.

Local Claude Code only. The Workflow fans out agent() sub-agents and relies on a persistent local filesystem (~/.releases/work/) and the CLI's RELEASES_API_* env. It is not deployed to the managed-agent fleet.

When to use

• A source has substantial history to backfill and running the remote update workflow per window is too expensive.
• A remote fetch burned an extraction loop and wrote 0 releases — extracting locally sidesteps the loop.

When NOT to use

• A clean feed / GitHub source — just add it (managing-sources) and let cron fetch it.
• Inside a managed-agent session — this is local-only.
• A publisher opt-out — the preflight gate refuses it (see below).

Cost contract